A Path Relinking-Based Scatter Search for the Resource-Constrained Project Scheduling Problem

Project scheduling has received a growing attention from researchers for the last decades in order to propose models and methods to tackle scheduling problems for real-size projects. In this paper, we consider the resource-constrained project scheduling problem (RCPSP), which consists in scheduling the activities in order to minimize the project duration in presence of precedence and resource constraints. As this problem is NP-hard, we propose a hybrid metaheuristic based on scatter search that involves forward-backward improvement and reversing the project network at each iteration of the scatter search. A bidirectional path relinking method with a new move is used as combination method. An advanced parameter tuning method based on local search is employed. The proposed method is applied on the standard benchmark projects of size 30, 60 and 120 activities from the PSPLIB library and compared with the state-of-the-art heuristics of the literature. The computational results show that the proposed hybrid scatter search produces high-quality solutions in reasonable computational time and is among the best performing metaheuristics.